@crepels Nice article! In particular, this is the best explanation I've seen yet of the "infinite signature recursion" problem, and the way around it.

I haven't tried to talk to Threads from my own toy implementation yet. I have a suspicion that the "instance actor" requirement is going to give me a headache.

@FenTiger Thanks :)

I can't really make sense of the instance actor requirement. I only tried this from ActivityPub.Academy (i.e., Mastodon); it would be interesting if there are any differences with other services. If you try this out with your implementation at some point, I'd be interested to know what you find.

@crepels @FenTiger I spent *way* too long trying to figure out how to get my library (https://github.com/jahfer/clj-activitypub) to talk to Threads. Thank you! Your post was the thing that helped me to pull an actor document.

Being stubborn, I tried to get to the bottom of why the instance actor stuff was required. Turns out...it's not! Threads just requires that the signing actor has a `url` field, which isn't common except for the instance actor. How anticlimactic 😑 I'm going to flag this to the Threads folks.